This invention relates to a device for the sensing of the operating condition of a gearshift clutch. In particular, the invention concerns the sensing of the proper engagement position for turning on a gearshift clutch, such a clutch being activated by the axial movement of one of its sections.
The monitoring of the starting position is especially important with mechanical gear clutches, as well as electromagnetic gear clutches. When such clutches are engaged, two different engagement positions have to be considered. In the first engagement position, the teeth of the gear of one clutch section face the corresponding tooth gaps of the gear of the other clutch section. In this instance, the clutch is capable of engaging completely and can now transmit the full normal moment.
In the second engagement position, the teeth of the gear of one side face the teeth of the gear on the opposing side and upon coupling, the teeth remain in the "tooth-on-tooth" position. In this situation, the clutch can only transmit a small portion of the normal moment. If accelerated slowly, the clutch can slide from the "tooth-on-tooth" position into the desired "tooth-in-tooth" position (namely, the first engagement position), and is then completely engaged. However, with fast acceleration, the time for such an engagement is too short with the result that the tip of the teeth bounce against the flanks of the opposing teeth and are repelled causing the clutch to slip. This leads to damage of the gears and is therefore undesirable. It can only be avoided if one can reliably sense the "tooth-in-tooth" and "tooth-on-tooth" positions and can tell them apart.
In the case of electromagnetically activated gear clutches, it is customary to deal with the problem of the coupling position by superimposing an alternating current over the energizing direct current. In this instance, the variable alternating current resistance at open or engaged clutch positions (and thus open and closed magnetic circuits) is converted into a corresponding signal, through suitable circuitry. For this kind of sensing, however, a complicated and laborious installation is necessary.
It is also possible to provide an inductive circuit closer for the sensing of the engagement position. This closer circuit is activated by a circular lug which is fastened to the moving section of the clutch. Such a circular lug requires additional space which is not always available. In addition, extremely precise and true adjustments are necessary and this can cause difficulties.
The invention undertakes to provide a device for the sensing of the engagement positions of a clutch, which device quickly and reliably signals the current position of the moving section of the clutch. The device can be simply obtained by using as few parts as possible, the parts requiring little space and, above all, do not need to be affixed to the moving section. Possible breakdowns may accordingly be repaired easily and quickly and no extraordinary precision would be needed for the mounting of the additional parts to be installed. In addition, the device may be installed in existing clutches, quickly and simply.